Method for payment with cash card

ABSTRACT

Method for cash card payment in a payment station for debit and credit cards. The invention is characterised in that the cash card ( 1 ) comprises a processor and is caused to store a unique identity associated with a money amount, which exists at a money institution ( 3 ), such as a central bank, or which is caused to be transferred from a bank account or the corresponding, to the money institution, in that the transferred amount is caused to be stored on the cash card ( 1 ), in that the amount lacks a connection to the proprietor of the cash card except via the said identity, in that, at payment using the cash card ( 1 ), the amount to be paid is caused to be transferred, together with the said identity, from the cash card ( 1 ) to a payment terminal ( 5 ) comprising the said payment station, in that the payment terminal ( 5 ) is caused to store the paid amount together with the said identity and that a remaining amount after payment is counted down on the cash card and is stored on the cash card, and in that the payment terminal ( 5 ) is caused to activate the money institution ( 3 ) to transfer, using the identity, the amount to be paid using the cash card ( 1 ) to an account ( 7 ) belonging to the point of sale where the payment terminal ( 5 ) is located.

The present invention relates to a method for payment with a cash cardin the form of a card, like a credit card, a mobile telephone or atablet computer for payment in a payment station for debit and creditcards, or another corresponding carrier. In the following, such carriersare termed cash cards.

Cash, bills and coins, is a practical and quick payment means, inparticular for smaller money amounts. However, cash also has drawbacks,use and circulation of cash require counting, usually several timesduring a cycle from central bank to bank to consumer to point of saleand back to bank and central bank. The circulation of physical cash alsorequires costly transport, which in turn constitutes a risk exposure aslarger volumes are handled, and facilitates robberies and robberyattempts.

It is usually the central banks that administer and finance themanufacture and distribution of such cash. The end customer does not seethese costs that are split between merchants and banks, includingcentral banks.

During the last several decades, debit and credit cards have come toreplace cash for a large part of “larger” payments, and this trend isprogressing downwards to smaller money amounts. The use of these cardsis today cheaper than cash, as viewed from a societal perspective, butis also associated with costs for administration and risk (card fraud).In this case, these costs are split between the end customer and thepoint of sale, while the card companies and the bank system usually gainfrom the system. Central banks are not affected.

The cards used in these systems do not keep any money, they onlyconstitute an identifier for being able to authenticate (using a PINcode) a specific registered user who is to be debited and invoiced thetransaction which at each time is requested. The card emitting partypays money to the merchant, and periodically invoices the user, in caseof a credit card, or debits the user's account, in case of a debit cardconnected to an own account. In order to maintain a certain security, ateach transaction checks are performed regarding availability of fundsand whether the user pays his or her invoices, if the user respects thecurrent credit limit and if the card is blocked. This takes a certainamount of time, requires communication online and of course is alsoassociated with certain costs.

The following is a description of a system, which mimics physical cashmanagement but without physical cash in the form of bills and coins. Thesystem comprises three central components or devices. These devices arean emitting party, a so called trusted partner; a carrier device, whichmay be for instance a so called smartcard, or a mobile telephone whichcomprises a SIM card which actually is a smartcard, or anothercomparable device; and a device for receiving a payment, which may forexample be a so called payment terminal or a POS (Point Of Sale)terminal which exists at almost all payment locations today.

Hence, the present invention relates to a method for cash card paymentin a payment station for debit and credit cards, and is characterised inthat the cash card comprises a processor and is caused to store a uniqueidentity associated with a money amount, which exists at a moneyinstitution, such as a central bank, or which is caused to betransferred from a bank account or the corresponding, to the moneyinstitution, in that the transferred amount is caused to be stored onthe cash card, in that the amount lacks a connection to the proprietorof the cash card except via the said identity, in that, at payment usingthe cash card, the amount to be paid is caused to be transferred,together with the said identity, from the cash card to a paymentterminal comprising the said payment station, in that the paymentterminal is caused to store the paid amount together with the saididentity and that a remaining amount after payment is counted down onthe cash card and is stored on the cash card, and in that the paymentterminal is caused to activate the money institution to transfer, usingthe identity, the amount to be paid using the cash card to an accountbelonging to the point of sale where the payment terminal is located.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic block diagram of an exemplary, non-limitingembodiment of system implementation one or more aspects.

DETAILED DESCRIPTION

Below, the invention is described in closer detail, partly in connectionto an exemplifying embodiment illustrated in FIG. 1.

The invention relates to a method for cash card payment in a paymentstation for debit and credit cards. The purpose is to, for a payment,replace physical cash, in the form of bills and coins, with virtual cashstored at a card corresponding to a debit or credit card.

According to the invention, the cash card 1 comprises a processor 2. Thecash card is caused to store a unique identity associated with an amountof money, which exists at a money institution 3, such as a central bank,or which is caused to be transferred from a bank account or thecorresponding, to the money institution 3. The amount is caused to bestored on the cash card 1, as is illustrated by arrow 4 in FIG. 1.

The amount lacks any connection to the proprietor of the cash card,except via said identity, why the cash card as such is anonymous.

The cash card does not contain any information about the account numberfrom which money is transferred to the money institution.

The identity may, among other things, be used to designate the moneyinstitution from which money was initially transferred, or to whichmoney institution money was transferred.

At the time of payment using the cash card, the amount to be paid iscaused to be transferred, together with the said identity, from the cashcard 1 to a payment terminal 5 connected to the said payment station.The payment terminal with the payment station is suitably of the sametype as conventional payment terminals for debit or credit cards. Thecash card communicates with the payment terminal.

The payment terminal is caused to store the paid amount together withthe said identity, and a remaining amount after the payment is counteddown on the cash card and is stored on the cash card. Counting down mayalternatively take place in the payment terminal.

The present invention can be adapted to function online or offline, evenif the offline case is preferred.

Thereafter, the payment terminal 5 is caused to contact, and therebyactivate, the money institution 3 for transferring, using the identity,the amount which is paid using the cash card 1, as is illustrated by thearrow 6, to an account 7 belonging to the point of sale at which thepayment terminal is located, which is illustrated by arrow 8.

In case the purchase and the transfer of the amount to the seller'saccount take place simultaneously, it is an online purchase.

This way, a payment is performed, corresponding to a cash payment usingphysical money, where there are no connections between the cash card andthe proprietor of the cash card.

Anyone can use the cash card for a payment, under condition that thecash card contains a required amount of money, as is the case withphysical money.

The above described relates to a simple embodiment of the invention.However, there is a need to increase the security during the varioustransfers, why an embodiment with higher security is described in thefollowing.

Also according to this embodiment, the cash card 1 is caused to store aunique identity but also a secret cryptographic key which is associatedwith an amount of money, which exists at the money institution, or whichis caused to be transferred from a bank account or the corresponding, tothe money institution 3. The amount lacks any connection to theproprietor of the cash card 1, except for via the said identity.

At the time of payment using the cash card 1, the amount to be paid,together with the said identity and any additional parameters, such asin the form of time of purchase, current amount and/or a random number,as well as a number calculated using the secret cryptographic key and bythe cash card processor, is transferred from the cash card to a paymentterminal 5, which is illustrated by the broken arrow 9. The paymentterminal 5 is caused to store the current amount together with the saidcalculated number.

Thereafter, the payment terminal is caused to perform a calculationusing the parameters that were used to perform the said calculation bythe cash card processor, using the cash card's public cryptographic key.At a match between the number calculated by the cash card processor andthe number calculated by the payment terminal, the payment terminal iscaused to store the current transaction and to activate the moneyinstitution 3, which is illustrated using the broken arrow 10, toreimburse, using the cash card 1 identity, the amount to be paid to anaccount 7 belonging to the point of sale at which the payment terminal 5is located, which is illustrated using the broken arrow 11. Usually,there will be a time difference between the counting down of the cashcard amount and the transfer by the point of sale of the current amountor the daily statement. The amount on the cash card is caused to becounted down and to be stored after payment on the cash card 1. Whenpayment has taken place using the reimbursement, it is preferred thatthe counted down amount exists on the cash card in order to, at the nextpayment, be able to know the available amount.

According to a preferred embodiment, at the said activation of the moneyinstitution the payment terminal 5 is caused to calculate a number basedupon known parameters regarding the purchase and using a secretcryptographic key at the payment terminal. The payment terminal 5 iscaused to transfer the said parameters and the said number to the moneyinstitution, and the money institution is caused to perform acalculation using the same parameters and using the public cryptographickey of the payment terminal, and when there is a match the said transfertakes place to an account belonging to the point of sale.

Since it is possible to carry through with a purchase using the cashcard, this can be used to buy physical cash money at an automatic cashdispensing machine, such as an ATM.

By both the processor on the cash card, the payment terminal and themoney institution performing calculations using secret and publiccryptographic keys, the purchase, the payment terminal and also the cashcard are authenticated. Hence, this results in a very safe system whichis very difficult to manipulate.

According to a preferred embodiment, the said unique identity can beemitted by the money institution.

According to an alternative embodiment, the said unique identity iscaused to be emitted by the cash card emitter.

According to another preferred embodiment, the said unique identity isstored on the cash card in encrypted form, and the money institution hasa required decryption key.

According to an additional preferred embodiment, the cash card is causedto be stored in the memory or chip of a mobile telephone, and the mobiletelephone is caused to communicate with the said payment terminal duringa payment.

It is preferred that transmission of money to the cash card is caused totake place via a cash dispensing machine, such as an ATM or a chargingteller or a POS or a computer or a so called smartphone.

It is also preferred that the payment terminal is caused to verify thata sufficient amount is present on the cash card before the payment iseffected.

Above, a number of embodiments have been described. However, theinvention can be varied. Hence, the choice of parameters for performingthe above mentioned calculations can be other parameters than the onesmentioned above.

Therefore, the present invention is not to be considered limited to theabove described exemplifying embodiments, but may be varied within thescope of the enclosed claims.

The invention claimed is:
 1. A method comprising: storing proprietorinformation, associated with a cash card proprietor, at a moneyinstitution, wherein the proprietor information includes a proprietoridentity, an account number, a unique identity, and a money amount;storing, on a cash card, the unique identity, a secret cryptographickey, and a money amount available on the cash card, wherein the cashcard includes a processor, and wherein the cash card is linked to theproprietor by the unique identity and the proprietor identity, theaccount number, and the money amount at the money institution are notstored on the cash card; establishing communication between the cashcard and a payment terminal to initiate a transaction, the transactionbeing performed offline without a connection to any financialinstitution; transferring, from the cash card to the payment terminal,the unique identity and a first random number calculated by the cashcard using the secret cryptographic key; calculating, by the cash card,a new balance based on a payment amount of the money amount available onthe cash card, wherein the new balance is subsequently stored on thecash card as the money amount available on the cash card; calculating,at the payment terminal, a second random number using a publiccryptographic key associated with the cash card; determining, by thepayment terminal, a match between the first random number and the secondrandom number, wherein the match, when determined, authenticates thetransaction; storing, at the payment terminal, the unique identity andthe payment amount to complete the transaction between the cash card andthe payment terminal; establishing communication, after completion ofthe transaction, between the payment terminal and the money institution;and activating an online transfer of the payment amount from the moneyamount at the money institution associated with the proprietor to anaccount associated with the payment terminal based on the uniqueidentify, wherein the online transfer is authenticated using the uniqueidentity.
 2. The method according to claim 1, wherein, at the time oftransaction the cash card transfers to the payment terminal the paymentamount and the time of transaction.
 3. The method according to claim 1,wherein, the unique identity is encrypted on the cash card, and whereinthe money institution has a decryption key associated with the uniqueidentity.
 4. The method according to claim 1, wherein, the moneyinstitution produces the unique identity associated with a cash cardproprietor.
 5. The method according to claim 1, wherein, a trustedpartner produces the cash card and the unique identity associated with acash card proprietor.
 6. The method according to claim 1, wherein, thecash card functions from a mobile phone, such that the mobile phonecommunicates with the payment terminal.
 7. The method according to claim1, wherein, the payment terminal is a cash dispensing machine.
 8. Themethod according to claim 1, wherein, the payment terminal verifiespayment amount is available on the cash card before completing thetransfer.